In an example, a method includes, at least one processor, in response to each of a plurality of requests, determining a halftone screen. Determining the halftone screen comprises encoding a signature pattern in the halftone screen, and halftone screens for different requests may be encoded with a different signature pattern. The halftone screen may be arranged such that, when applied to image data to provide a printed output, the pattern is discernible therein to provide a signature for the printed output.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
2. A method according to claim 1 further comprising transmitting each halftone screen to an entity identified in the request.
A method for processing halftone screens in a printing system involves generating multiple halftone screens from a single input image, where each screen is optimized for different printing conditions or substrates. The method includes receiving a request specifying parameters such as print resolution, substrate type, or ink characteristics, and then generating a set of halftone screens tailored to those parameters. Each halftone screen is designed to produce optimal print quality under the specified conditions. The method further includes transmitting each generated halftone screen to an entity identified in the request, such as a printer, a print server, or a storage system, ensuring that the appropriate screen is used for the intended printing task. This approach improves print consistency and quality by dynamically adapting halftone patterns to varying printing environments. The method may also involve storing the generated halftone screens for future use or sharing them across multiple printing devices. By automating the generation and distribution of halftone screens, the method reduces manual intervention and enhances efficiency in print production workflows.
3. A method according to claim 2 further comprising encrypting each halftone screen and transmitting the encrypted halftone screen.
A method for secure halftone image processing involves generating multiple halftone screens from an original image, where each halftone screen represents the image with different visual characteristics. These screens are then combined to reconstruct the original image, enhancing security by making it difficult to discern the original content from any single screen. The method further includes encrypting each halftone screen before transmission to prevent unauthorized access or tampering during transfer. The encrypted screens are transmitted to a recipient, who decrypts and combines them to recover the original image. This approach ensures that even if an individual halftone screen is intercepted, the original image remains protected due to the encryption and the need for multiple screens to reconstruct it. The technique is particularly useful in secure image transmission systems where confidentiality and integrity are critical.
4. A method according to claim 2 further comprising storing an indication of each signature in association with an identity of each entity to which the halftone screen was transmitted.
A method for managing halftone screen signatures in a digital printing system involves generating a unique signature for each halftone screen used in the system. The signature is derived from the halftone screen's properties, such as its pattern, frequency, or angle, ensuring that each screen can be distinctly identified. The method further includes transmitting the halftone screen to one or more entities, such as printers or printing devices, and storing an indication of each signature in association with the identity of each entity to which the halftone screen was transmitted. This allows for tracking which halftone screens are used by which entities, enabling better management of screen distribution, usage monitoring, and potential security or licensing enforcement. The method ensures that the relationship between halftone screens and their recipients is recorded, facilitating auditing and compliance in printing workflows. The stored associations can be used to verify screen usage, detect unauthorized distribution, or optimize screen allocation across different printing devices.
5. A method according to claim 4 wherein storing the indication of each signature comprises securely storing the indication.
The invention relates to secure data storage systems, specifically methods for securely storing digital signatures to prevent unauthorized access or tampering. The problem addressed is ensuring the integrity and confidentiality of stored signature data, which is critical in applications like authentication, document verification, and blockchain transactions. The method involves securely storing an indication of each digital signature generated during a process. This indication may include the signature itself, a hash of the signature, or a reference to the signature. Security measures are implemented to protect the stored indication from unauthorized access, modification, or deletion. These measures may include encryption, access controls, or tamper-evident storage mechanisms. The method is part of a broader system for generating and managing digital signatures. Initially, a request to generate a signature is received, and the signature is generated using a cryptographic key. The generated signature is then stored securely, along with metadata such as a timestamp or the identity of the signing entity. The secure storage ensures that the signature cannot be altered without detection, maintaining its validity for future verification. This approach is particularly useful in environments where the integrity of digital signatures is critical, such as financial transactions, legal documents, or supply chain tracking. By securely storing the signature indication, the system ensures that the signature remains trustworthy and verifiable over time.
9. A method according to claim 1, wherein the halftone screen includes a matrix of threshold values that corresponds to the signature pattern.
A method for generating halftone images with embedded signature patterns involves creating a halftone screen that includes a matrix of threshold values corresponding to a specific signature pattern. The halftone screen is used to convert continuous-tone images into halftone images, where the threshold values determine the placement of dots or pixels in the output. The signature pattern is embedded within the halftone screen, allowing the pattern to be visually or digitally detected in the resulting halftone image. This technique is useful in applications such as document security, authentication, and anti-counterfeiting, where hidden patterns or watermarks are required. The method ensures that the signature pattern is imperceptible or minimally perceptible to the human eye while remaining detectable through specialized analysis. The threshold values in the matrix are arranged in a way that the signature pattern is preserved during the halftoning process, maintaining its integrity for verification purposes. This approach enhances the security of printed or displayed images by embedding covert information that can be used to verify authenticity or detect tampering.
10. A method according to claim 1, wherein applying the halftone screen to the image data includes associating a pixel of the halftone screen with a pixel of the image data, comparing a pixel value of the image data with a threshold value of the pixel of the halftone screen, and determining print instructions for the pixel of image data based on a result of the comparison.
This invention relates to digital halftoning techniques used in printing systems to reproduce continuous-tone images with limited color or grayscale output. The problem addressed is efficiently converting high-resolution image data into printable binary or multi-level dot patterns while maintaining visual quality. The method involves applying a halftone screen to image data by associating each pixel of the halftone screen with a corresponding pixel in the image data. For each pixel pair, the image pixel's value is compared against a threshold value from the halftone screen. Based on this comparison, print instructions are generated for the image pixel. The halftone screen may use a periodic pattern or error diffusion to distribute dots in a way that approximates the original image's tonal gradations. This process ensures that the printed output accurately represents the original image's shading and detail, even when using limited color or grayscale capabilities. The method is particularly useful in digital printing, where precise control over dot placement is required to achieve high-quality reproductions.
13. A method according to claim 12 wherein accessing the halftone signature comprises accessing a pattern encoding the signature and determining, based on the digital sample, whether the printed image comprises the pattern.
The invention relates to digital image analysis for detecting halftone signatures in printed materials. The problem addressed is the need to accurately identify and authenticate printed documents or images by analyzing their halftone patterns, which are often used for security or verification purposes. Halftoning is a technique that simulates continuous-tone imagery through the use of dots, lines, or other patterns, and these patterns can encode unique signatures for authentication. The method involves accessing a halftone signature, which is represented as a specific pattern. The signature is embedded within the printed image during the printing process. To detect the signature, a digital sample of the printed image is obtained, typically through scanning or photography. The system then analyzes the digital sample to determine whether the printed image contains the encoded pattern. This detection process may involve pattern recognition algorithms, image processing techniques, or other computational methods to compare the digital sample against the known halftone signature. The method ensures that the printed image can be verified as authentic by confirming the presence of the expected halftone pattern. This is particularly useful in applications such as document security, anti-counterfeiting, and quality control in printing. The technique leverages the inherent properties of halftoning to embed and retrieve information without altering the visual appearance of the printed material significantly. The system may also include preprocessing steps to enhance the digital sample, such as noise reduction or contrast adjustment, to improve the accuracy of signature detection.
14. A method according to claim 11 wherein the determining if the printed image contains the halftone signature comprises determining a fuzzy match which allows for randomisation introduced by the printing process.
The invention relates to image processing and authentication, specifically detecting halftone signatures in printed images to verify authenticity. The problem addressed is the difficulty in accurately identifying halftone patterns in printed images due to variations introduced by the printing process, such as ink spread, dot gain, or misregistration, which can distort the intended pattern. The method involves analyzing a printed image to determine if it contains a predefined halftone signature. The key innovation is the use of a fuzzy matching technique that accounts for random variations caused by printing. This approach allows the system to recognize the signature even when the printed pattern deviates slightly from the original due to process inconsistencies. The fuzzy matching may involve comparing the printed image to a reference signature while tolerating minor deviations within a defined threshold. This ensures robust detection despite printing-induced distortions. The method may also include preprocessing steps to enhance the image before analysis, such as noise reduction or contrast adjustment, to improve the accuracy of the fuzzy matching. The halftone signature itself may be embedded in the image as a subtle pattern that is imperceptible to the human eye but detectable through image processing techniques. This technique is useful for applications like document authentication, anti-counterfeiting, and quality control in printing.
16. Processing apparatus according to claim 15 in which the security module is to securely store an indication of the pattern.
The invention relates to processing apparatus with enhanced security features for storing and verifying access patterns. The apparatus includes a security module that securely stores an indication of a pattern, which may be a user-defined or system-generated sequence used for authentication or access control. The security module ensures that the pattern is stored in a tamper-resistant manner, preventing unauthorized access or modification. This is particularly useful in systems where secure authentication is required, such as financial transactions, biometric verification, or access to sensitive data. The apparatus may also include a processor to execute instructions related to the pattern, such as comparing an input pattern to the stored indication to determine if access should be granted. The security module may further include cryptographic functions to encrypt the stored pattern or generate secure hashes for verification. This design ensures that even if the apparatus is compromised, the pattern remains protected, enhancing overall system security. The invention addresses the problem of insecure storage of authentication patterns, which can lead to unauthorized access or data breaches. By securely storing the pattern indication, the apparatus mitigates these risks while maintaining efficient access control.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
January 30, 2020
May 7, 2024
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.